How the amount of fish you eat impacts water quality

Idaho plans to conduct a $300,000 study to learn how much fish its residents eat from state waters. The amount consumed helps determine regulatory limits for pollutant levels in rivers and lakes. Most Western states use the EPA's default fish-consumption rate, a cracker-sized 17.5 grams per day, to set human health standards for dozens of chemicals in surface water, and some chemicals in fish tissue.

But in Washington, Idaho and Oregon, where catching and consuming salmon, lamprey and sturgeon is a way of life, that default isn't enough to protect sport anglers, tribal members and others from cancer-causing pollutants and methylmercury, which accumulates in the food chain and can cause neurological problems. "If we don't have healthy fish to eat, we as a people won't survive," says Russ Hepfer, vice chairman of Washington's Lower Elwha Klallam Tribe.

In 2011, Oregon adopted a fish consumption rate 10 times higher than the EPA's default and strengthened its water-quality standards accordingly. But Idaho and Washington's consumption assumptions are still much lower, and their rules for industries and wastewater treatment plants are less strict. In 2006, Idaho proposed going from the EPA's old default of 6.5 grams per day to the current recommendation of 17.5 grams per day. But last year, the EPA told Idaho that 17.5 is too low, because that level fails to protect residents such as the Nez Perce who eat much more fish. Thus Idaho is launching its new study. Washington is currently revising its regulations; the EPA and tribal representatives are urging both states to follow Oregon's lead. Alaska is beginning a similar review. After all, political boundaries are meaningless to fish and rivers.